The present invention broadly relates to an apparatus for the hydraulic transmission of mechanical power and for the simultaneous multiplication or step-up of the speed of rotation.
Generally speaking, the apparatus of the present invention is capable of transmitting power from a comparatively slow-running drive means to a comparatively fast-running power load or driven means, wherein the drive means and the power load or driven means can be separated so remotely from one another such that even though a conventional belt drive or transmission or gear transmission or gearbox is impractical other suitable power transmitting means can be reliably interposed between the drive means and the driven means.
A typical examplary application for such a power transmission is to transmit the power of a low pressure water turbine, which is installed at as low a level as possible, to a generator, which is preferably constructed at the floor level of related machinery. As a result of the small pressure head of the turbine, the turbine must rotate slowly, wherein a typical speed of rotation is approximately 100 rpm. On the other hand, the generator should run relatively fast, e.g. between 1,000 and 1,500 rpm, since more efficient electrical designs are possible with this type of generator than with slower-running four-pole generators.
A rotary speed step-up or multiplication ratio of 1:10 or 1:15 is thus desirable. Even if spatial conditions would permit a conventional arrangment such as a belt or gear drive, such a large step-up ratio would cause difficulties with power transmission by gearboxes or belt drives, especially due. to the disproportionately small size of the pinion or the smaller belt pulley in relation the larger gear or pulley.
The above discussion indicates the need for a power transmission apparatus of a new type of construction which has a high speed step-up or multiplication ratio.
For all types of power transmission, hydraulic direct-flow transmission means are known which employ oil or hydraulic fluid pumps, pressure transmission pipelines or conduit means, oil or hydraulic motors, and return pipelines or conduit means, supplemented by auxiliary systems for filling, cooling and filtering.
For transmitting high power at high levels or rates, for example in the megawatt range, relatively high pressures must generally be employed which results in the problem well known to the person skilled in the art, of considerable noise from pumps and motors and, likewise, the problem of the degree of efficiency of power transmission, which at best falls in the range of up to 80%. This is obviously considerably less than 90% or above, such as would be achievable with power transmission by gearboxes or belt transmission drive means.